Method and apparatus for closed loop data transmission
A method for communicating a plurality of data streams between a transmitting device with multiple transmit antennas and a receiving device, is disclosed. The method comprises determining a set of power weightings, efficiently quantizing the power weightings, and providing the set of power weightings the transmitting device. Another aspect of the invention comprises the transmitter implicitly signaling the number of data streams which the receiver should feedback information for through the amount of feedback requested. An additional aspect of the invention is a means of determining the best codebook weights by combining the maximum power and maximum capacity criteria.
1. A method comprising the steps of:
receiving a plurality of bits representing power weightings information, wherein information representing a first power weighting is represented by a first number of bits, and information representing a second power weighting is represented by a second number of bits, wherein the first number of bits is larger than the second number of bits;
determining the first power weighting value for a first data stream from the first number of bits, wherein the first power weighting value can take on values within a first range;
determining the second power weighting value for a second stream from the second number of bits, wherein the second power weighting value can take on values within a second range, wherein the second range is based on the first power weighting value; and
transmitting data streams weighted by the power weighting values.
2. The method of claim 1 further comprising the step of:
transmitting information regarding the first and the second power weightings.
3. The method of claim 2 wherein the step of transmitting information regarding the first and the second power weightings comprises the step of transmitting the power weightings from a largest value to a smallest value.
4. The method of claim 2 wherein the step of transmitting information regarding the first and the second power weightings comprises the step of transmitting a square root of the first and the second power weightings.
5. The method of claim 1 further comprising the step of:
receiving data streams weighted by the first and the second power weighting values.
6. An apparatus comprising:
a receiver receiving a plurality of bits representing power weighting values, wherein a first power weighting value is represented by a first number of bits, and a second power weighting value is represented by a second number of bits, wherein the first number of bits is larger than the second number of bits; and wherein the first power weighting value can take on values within a first range and the second power weighting value can take on values within a second range, wherein the second range is based on the first power weighting value; and
a transmitter transmitting data streams weighted by the power weighting values.
7. The apparatus of claim 6 further comprising the step of:
a receiver receiving data streams weighted by the power weighting values.
8. The apparatus of claim 6 further comprising the step of:
transmitting information regarding the of power weighting values.
9. The apparatus of claim 8 wherein the information regarding the power weighting values is transmitted from a largest value to a smallest value.
10. The apparatus of claim 8 wherein the information regarding the power weighting values comprises a square root of the power weighting values.
11. The apparatus of claim 8 wherein the information regarding the plurality of power weighting values is transmitted from a largest value to a smallest value.